JP2020158001A - Road surface state estimation device - Google Patents

Road surface state estimation device Download PDF

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JP2020158001A
JP2020158001A JP2019061172A JP2019061172A JP2020158001A JP 2020158001 A JP2020158001 A JP 2020158001A JP 2019061172 A JP2019061172 A JP 2019061172A JP 2019061172 A JP2019061172 A JP 2019061172A JP 2020158001 A JP2020158001 A JP 2020158001A
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Prior art keywords
wheels
wheel
vehicle
driven
road surface
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碩 野間
Hiroshi Noma
碩 野間
丹羽　栄二
Eiji Niwa
栄二 丹羽
川崎　裕章
Hiroaki Kawasaki
裕章 川崎
悠輔 前田
Yusuke Maeda
悠輔 前田
小川　文治
Bunji Ogawa
文治 小川
加藤　和広
Kazuhiro Kato
和広 加藤
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Sumitomo Rubber Industries Ltd
Aisin AW Co Ltd
Advics Co Ltd
Aisin Corp
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Aisin Seiki Co Ltd
Sumitomo Rubber Industries Ltd
Aisin AW Co Ltd
Advics Co Ltd
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Application filed by Aisin Seiki Co Ltd, Sumitomo Rubber Industries Ltd, Aisin AW Co Ltd, Advics Co Ltd filed Critical Aisin Seiki Co Ltd
Priority to JP2019061172A priority Critical patent/JP2020158001A/en
Priority to CN202010161937.2A priority patent/CN111746546A/en
Priority to US16/813,916 priority patent/US20200307607A1/en
Priority to EP20162448.3A priority patent/EP3715205A3/en
Publication of JP2020158001A publication Critical patent/JP2020158001A/en
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
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    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
    • B60W40/06—Road conditions
    • B60W40/068—Road friction coefficient
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
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    • B60K7/0007—Disposition of motor in, or adjacent to, traction wheel the motor being electric
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
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    • G01—MEASURING; TESTING
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    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/46—Drive Train control parameters related to wheels
    • B60L2240/465—Slip
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    • B60—VEHICLES IN GENERAL
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    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/60—Navigation input
    • B60L2240/64—Road conditions
    • B60L2240/642—Slope of road
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2260/00—Operating Modes
    • B60L2260/20—Drive modes; Transition between modes
    • B60L2260/28—Four wheel or all wheel drive
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B60L2260/00—Operating Modes
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    • B60L2260/44—Control modes by parameter estimation
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    • B60—VEHICLES IN GENERAL
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Abstract

To appropriately estimate a coefficient of friction of a road surface using a four-wheel independent driving type vehicle.SOLUTION: A road surface state estimation device includes: a control part which controls a driving device that each independently can drive a plurality of wheels so that a part of the plurality of wheels provided on a vehicle traveling on a road surface is driven as a driving wheel and a remaining part of the plurality of wheels is driven as a driven wheel; an acquisition part which acquires a detection result of a plurality of wheel speed sensors each detecting rotation speeds of the plurality of wheels; and an estimation part which calculates slip ratios for each of the driving wheels based on the detection result of a first wheel speed sensor detecting the rotation speed of the driving wheel in the plurality of wheel speed sensors and a detection result of a second wheel speed sensor detecting the rotation speed of the driven wheel in the plurality of wheel speed sensors, and estimates the coefficient of friction in each region corresponding to the driving wheels on the road surface based on the slip ratios.SELECTED DRAWING: Figure 2

Description

本開示は、路面状態推定装置に関する。 The present disclosure relates to a road surface condition estimation device.

従来から、車両が走行する路面の摩擦係数を求める技術について検討されている。このような技術として、たとえば、駆動輪として駆動する２つの車輪と、従動輪として従動する２つの車輪と、が予め決められた二輪駆動方式の車両において、駆動輪として駆動する２つの車輪の回転速度の平均値と、従動輪として駆動する２つの車輪の回転速度の平均値と、に基づいてスリップ比を算出し、当該スリップ比に基づいて路面の摩擦係数を推定する技術が知られている。 Conventionally, a technique for obtaining the coefficient of friction of the road surface on which a vehicle travels has been studied. As such a technique, for example, in a vehicle of a two-wheel drive system in which two wheels driven as driving wheels and two wheels driven as driven wheels are determined in advance, rotation of the two wheels driven as driving wheels A technique is known in which a slip ratio is calculated based on an average value of speeds and an average value of rotation speeds of two wheels driven as driven wheels, and a friction coefficient of a road surface is estimated based on the slip ratio. ..

特開２００１−２５３３３４号公報Japanese Unexamined Patent Publication No. 2001-253334

しかしながら、上記のような従来の技術は、駆動輪および従動輪の個数および位置が固定であることが前提となっているので、駆動輪および従動輪の個数および位置が様々に変化しうる、いわゆる四輪独立駆動方式の車両にそのまま適用することができない。 However, since the conventional technique as described above is based on the premise that the number and position of the driving wheels and the driven wheels are fixed, the number and positions of the driving wheels and the driven wheels can be changed in various ways, so-called. It cannot be applied as it is to a vehicle with a four-wheel independent drive system.

そこで、本開示の課題の一つは、四輪独立駆動方式の車両を利用して路面の摩擦係数を適切に推定することが可能な路面状態推定装置を提供することである。 Therefore, one of the problems of the present disclosure is to provide a road surface condition estimation device capable of appropriately estimating the friction coefficient of the road surface by using a vehicle of a four-wheel independent drive system.

本開示の一例としての路面状態推定装置は、路面を走行する車両に設けられた複数の車輪のうち一部が駆動輪として駆動し、複数の車輪のうち残りの一部が従動輪として従動するように、複数の車輪をそれぞれ独立に駆動可能な駆動装置を制御する制御部と、複数の車輪の回転速度をそれぞれ検出する複数の車輪速センサの検出結果を取得する取得部と、複数の車輪速センサのうち駆動輪の回転速度を検出する第１の車輪速センサの検出結果と、複数の車輪速センサのうち従動輪の回転速度を検出する第２の車輪速センサの検出結果と、に基づいて、駆動輪ごとにスリップ比を算出し、当該スリップ比に基づいて、路面上における駆動輪に対応した領域ごとに摩擦係数を推定する推定部と、を備える。 In the road surface condition estimation device as an example of the present disclosure, a part of the plurality of wheels provided on the vehicle traveling on the road surface is driven as a driving wheel, and the remaining part of the plurality of wheels is driven as a driven wheel. As described above, a control unit that controls a drive device that can independently drive a plurality of wheels, an acquisition unit that acquires detection results of a plurality of wheel speed sensors that detect the rotation speeds of the plurality of wheels, and a plurality of wheels. Among the speed sensors, the detection result of the first wheel speed sensor that detects the rotation speed of the driving wheels and the detection result of the second wheel speed sensor that detects the rotation speed of the driven wheels among the plurality of wheel speed sensors are Based on this, a slip ratio is calculated for each drive wheel, and an estimation unit for estimating a friction coefficient for each region corresponding to the drive wheels on the road surface based on the slip ratio is provided.

上記のような構成によれば、四輪独立駆動方式の車両を利用して、駆動輪および従動輪の個数および位置に関わらず、路面の摩擦係数を、駆動輪に対応した領域ごとに適切に推定することができる。 According to the above configuration, using a four-wheel independent drive system vehicle, the friction coefficient of the road surface can be appropriately set for each region corresponding to the drive wheels regardless of the number and position of the drive wheels and the driven wheels. Can be estimated.

上述した路面状態推定装置において、推定部は、駆動輪および従動輪がそれぞれ複数存在する場合、第１の車輪速センサの検出結果に基づいて取得される複数の駆動輪の各々の回転速度と、第２の車輪速センサの検出結果に基づいて取得される複数の従動輪の回転速度の平均値と、に基づいて、駆動輪ごとにスリップ比を算出する。このような構成によれば、従動輪の回転速度については平均をとることで合わせて考慮し、駆動輪の回転速度については個別に考慮することで、駆動輪ごとにスリップ比を容易に算出することができる。 In the road surface condition estimation device described above, when there are a plurality of drive wheels and a plurality of driven wheels, the estimation unit determines the rotation speed of each of the plurality of drive wheels acquired based on the detection result of the first wheel speed sensor. The slip ratio is calculated for each drive wheel based on the average value of the rotation speeds of the plurality of driven wheels acquired based on the detection result of the second wheel speed sensor. According to such a configuration, the rotation speed of the driven wheels is taken into consideration by taking an average, and the rotation speed of the driving wheels is taken into consideration individually, so that the slip ratio can be easily calculated for each driving wheel. be able to.

また、上述した路面状態推定装置において、取得部は、複数の車輪の回転速度をそれぞれ検出する複数の車輪速センサを含む、車両の走行状態に関する情報を検出する車載センサの検出結果を取得し、制御部は、車載センサの検出結果に応じて、駆動輪として駆動させる車輪と、従動輪として駆動させる車輪と、を決定する。このような構成によれば、車両の走行状態を考慮して、駆動輪および従動輪の個数および位置を適切に決定することができる。 Further, in the road surface condition estimation device described above, the acquisition unit acquires the detection result of the in-vehicle sensor that detects the information on the driving state of the vehicle, including the plurality of wheel speed sensors that detect the rotation speeds of the plurality of wheels. The control unit determines a wheel to be driven as a driving wheel and a wheel to be driven as a driven wheel according to the detection result of the vehicle-mounted sensor. According to such a configuration, the number and position of the driving wheels and the driven wheels can be appropriately determined in consideration of the traveling state of the vehicle.

車載センサの検出結果に応じて駆動輪として駆動させる車輪と従動輪として駆動させる車輪とを決定する上述した構成において、制御部は、車載センサの検出結果が、車両が路面としての傾斜面を上る方向に進むことを示す場合、複数の車輪のうち車両の進行方向の前側に設けられた複数の前側車輪が、複数の車輪のうち車両の進行方向の後側に設けられた複数の後側車輪よりも数多く駆動輪として駆動するように、駆動装置を制御し、車両の走行状態が、車両が傾斜面を下る方向に進むという状態である場合、複数の後側車輪が複数の前側車輪よりも数多く駆動輪として駆動するように、駆動装置を制御する。このような構成によれば、登坂時には、車両を前から引っ張る形で駆動力が発生するように前側車輪の方を数多く駆動輪とすることで、車両の挙動を安定化させながら、摩擦係数を適切に推定することができる。また、降坂時には、たとえば回生ブレーキをかけた際に車両を後ろから引っ張る形で制動力が発生するように後側車輪の方を数多く駆動輪とすることで、車両の挙動を安定化させながら、摩擦係数を適切に推定することができる。 In the above-described configuration in which the wheels to be driven as the driving wheels and the wheels to be driven as the driven wheels are determined according to the detection result of the in-vehicle sensor, the control unit determines that the detection result of the in-vehicle sensor is that the vehicle climbs the inclined surface as the road surface. When indicating that the vehicle travels in a direction, the plurality of front wheels provided on the front side in the traveling direction of the vehicle among the plurality of wheels are the plurality of rear wheels provided on the rear side in the traveling direction of the vehicle among the plurality of wheels. If the drive is controlled so that it is driven as more drive wheels than, and the vehicle is in a state of traveling down an inclined surface, then the plurality of rear wheels is more than the plurality of front wheels. The drive device is controlled so that it is driven as many drive wheels. According to such a configuration, when climbing a slope, a large number of front wheels are used as driving wheels so that a driving force is generated by pulling the vehicle from the front, thereby stabilizing the behavior of the vehicle and reducing the coefficient of friction. Can be estimated appropriately. In addition, when descending a slope, for example, when the regenerative brake is applied, the rear wheels are used as many driving wheels so that braking force is generated by pulling the vehicle from behind, thereby stabilizing the behavior of the vehicle. , The coefficient of friction can be estimated appropriately.

また、車載センサの検出結果に応じて駆動輪として駆動させる車輪と従動輪として駆動させる車輪とを決定する上述した構成において、制御部は、車載センサの検出結果が、車両が旋回を行うことを示す場合、複数の車輪のうち旋回の外側に設けられた複数の外側車輪が、複数の車輪のうち旋回の内側に設けられた複数の内側車輪よりも数多く駆動輪として駆動するように、駆動装置を制御する。このような構成によれば、外側車輪に内側車輪よりも大きな駆動力を発生させることで、旋回の際の車両の挙動の安定化を図りながら、摩擦係数を適切に推定することができる。 Further, in the above-described configuration in which the wheels to be driven as the driving wheels and the wheels to be driven as the driven wheels are determined according to the detection result of the in-vehicle sensor, the control unit determines that the vehicle turns by the detection result of the in-vehicle sensor. In the case of the present invention, the driving device is such that a plurality of outer wheels provided on the outer side of the turn among the plurality of wheels are driven as more drive wheels than a plurality of inner wheels provided on the inner side of the turn among the plurality of wheels. To control. According to such a configuration, by generating a driving force larger than that of the inner wheel on the outer wheel, the friction coefficient can be appropriately estimated while stabilizing the behavior of the vehicle when turning.

また、車載センサの検出結果に応じて駆動輪として駆動させる車輪と従動輪として駆動させる車輪とを決定する上述した構成において、制御部は、車載センサの検出結果が、車両が直進することを示す場合、複数の車輪のうち車両の左右方向の一方側で進行方向に沿って設けられた複数の一方車輪のうち少なくとも２つが駆動輪として駆動するか、または、複数の車輪のうち左右方向の他方側で進行方向に沿って設けられた複数の他方車輪のうち少なくとも２つが駆動輪として駆動するように、駆動装置を制御する。このような構成によれば、複数の一方車輪のうち少なくとも２つ、または、複数の他方車輪のうち少なくとも２つを駆動輪として駆動させることで、同じ位置（領域）の摩擦係数を２回推定し、摩擦係数の推定精度を高めることができる。 Further, in the above-described configuration in which the wheels to be driven as the driving wheels and the wheels to be driven as the driven wheels are determined according to the detection result of the in-vehicle sensor, the control unit indicates that the detection result of the in-vehicle sensor indicates that the vehicle travels straight. In the case, at least two of the plurality of wheels provided along the traveling direction on one side of the vehicle in the left-right direction are driven as driving wheels, or the other of the plurality of wheels in the left-right direction is driven. The drive device is controlled so that at least two of the other wheels provided along the traveling direction on the side are driven as drive wheels. According to such a configuration, the friction coefficient at the same position (region) is estimated twice by driving at least two of the plurality of one wheels or at least two of the plurality of other wheels as driving wheels. However, the estimation accuracy of the friction coefficient can be improved.

この場合において、制御部は、複数の一方車輪のうち少なくとも１つと、複数の他方車輪のうち少なくとも１つと、が駆動輪として駆動するように、駆動装置を制御し、推定部は、路面上における複数の一方車輪に対応した一方領域の摩擦係数としての第１の摩擦係数と、路面上における他方車輪に対応した他方領域の摩擦係数としての第２の摩擦係数と、を推定し、制御部は、第１の摩擦係数と第２の摩擦係数との大小関係に応じて、複数の一方車輪と複数の他方車輪とのうちいずれを数多く駆動輪として駆動させるかを決定する。このような構成によれば、たとえば、一方領域および他方領域のうち、駆動輪が一輪あたりに路面に伝達可能な駆動力が相対的に小さい滑りやすい方の領域に、駆動輪が一輪あたりに路面に伝達可能な駆動力が相対的に大きい滑りにくい方の領域よりも数多く駆動輪を配置することで、必要な駆動力を分散して確保しやすくすることができる。したがって、車両の挙動の安定化を図りながら、摩擦係数を適切に推定することができる。 In this case, the control unit controls the drive device so that at least one of the plurality of one wheels and at least one of the plurality of other wheels are driven as drive wheels, and the estimation unit is on the road surface. The control unit estimates the first friction coefficient as the friction coefficient of one region corresponding to a plurality of one wheels and the second friction coefficient as the friction coefficient of the other region corresponding to the other wheel on the road surface. , It is determined which of the plurality of one wheels and the plurality of other wheels is driven as a large number of driving wheels according to the magnitude relationship between the first friction coefficient and the second friction coefficient. According to such a configuration, for example, in one region and the other region, in the slippery region where the driving force that the driving wheels can transmit to the road surface per wheel is relatively small, the driving wheels are on the road surface per wheel. By arranging more driving wheels than in the non-slip area where the driving force that can be transmitted to the vehicle is relatively large, it is possible to disperse and secure the required driving force. Therefore, the coefficient of friction can be appropriately estimated while stabilizing the behavior of the vehicle.

上述した路面状態推定装置は、推定部により推定された摩擦係数と閾値との比較結果に応じて、車両に設けられた通知部を介して所定の通知を出力する出力部をさらに備える。このような構成によれば、車両の乗員に対して摩擦係数と閾値との比較結果に応じた通知を容易に出力することができる。 The road surface condition estimation device described above further includes an output unit that outputs a predetermined notification via a notification unit provided in the vehicle according to the comparison result between the friction coefficient estimated by the estimation unit and the threshold value. According to such a configuration, it is possible to easily output a notification according to the comparison result between the friction coefficient and the threshold value to the occupant of the vehicle.

また、上述した路面状態推定装置において、推定部は、摩擦係数を、路面上における駆動輪に対応した領域の位置に関する位置情報と対応付けて記憶部に記憶する。このような構成によれば、路面の摩擦係数を位置ごとに細かく分けて把握することができる。 Further, in the road surface state estimation device described above, the estimation unit stores the friction coefficient in the storage unit in association with the position information regarding the position of the region corresponding to the drive wheels on the road surface. According to such a configuration, the coefficient of friction of the road surface can be grasped by dividing it into small parts for each position.

図１は、実施形態にかかる車両の構成を示した例示的かつ模式的なブロック図である。FIG. 1 is an exemplary and schematic block diagram showing the configuration of the vehicle according to the embodiment. 図２は、実施形態にかかる路面状態推定装置の機能を示した例示的かつ模式的なブロック図である。FIG. 2 is an exemplary and schematic block diagram showing the function of the road surface condition estimation device according to the embodiment. 図３は、実施形態にかかる摩擦係数が記憶部に記憶される態様の一例を示した例示的かつ模式的な図である。FIG. 3 is an exemplary and schematic diagram showing an example of a mode in which the friction coefficient according to the embodiment is stored in the storage unit. 図４は、実施形態において実現されうる駆動輪および従動輪の設定の第１の例を示した例示的かつ模式的な図である。FIG. 4 is an exemplary and schematic diagram showing a first example of driving and trailing wheel settings that can be realized in an embodiment. 図５は、実施形態において実現されうる駆動輪および従動輪の設定の第２の例を示した例示的かつ模式的な図である。FIG. 5 is an exemplary and schematic diagram showing a second example of driving and trailing wheel settings that can be realized in an embodiment. 図６は、実施形態において実現されうる駆動輪および従動輪の設定の第３の例を示した例示的かつ模式的な図である。FIG. 6 is an exemplary and schematic diagram showing a third example of driving and trailing wheel settings that can be realized in an embodiment. 図７は、実施形態において実現されうる駆動輪および従動輪の設定の第４の例を示した例示的かつ模式的な図である。FIG. 7 is an exemplary and schematic diagram showing a fourth example of driving and trailing wheel settings that can be realized in an embodiment. 図８は、実施形態にかかる路面状態推定装置が路面の摩擦係数を推定するために実行する一連の処理を示した例示的かつ模式的なフローチャートである。FIG. 8 is an exemplary and schematic flowchart showing a series of processes performed by the road surface condition estimation device according to the embodiment for estimating the friction coefficient of the road surface.

以下、本開示の実施形態を図面に基づいて説明する。以下に説明される実施形態の構成、ならびに当該構成によってもたらされる作用および効果は、あくまで一例であって、以下の記載内容に限られるものではない。 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The configurations of the embodiments described below, and the actions and effects brought about by the configurations, are merely examples and are not limited to the contents described below.

図１は、実施形態にかかる車両Ｖの構成を示した例示的かつ模式的なブロック図である。図１に示されるように、実施形態にかかる車両Ｖは、前輪１０ＦＬおよび１０ＦＲと、後輪１０ＲＬおよび１０ＲＲと、を備えた四輪自動車として構成されている。なお、以下では、前輪１０ＦＬおよび１０ＦＲと、後輪１０ＲＬおよび１０ＲＲと、を総称して車輪１０と表現することがある。 FIG. 1 is an exemplary and schematic block diagram showing the configuration of the vehicle V according to the embodiment. As shown in FIG. 1, the vehicle V according to the embodiment is configured as a four-wheeled vehicle including front wheels 10FL and 10FR and rear wheels 10RL and 10RR. In the following, the front wheels 10FL and 10FR and the rear wheels 10RL and 10RR may be collectively referred to as the wheel 10.

実施形態にかかる車両Ｖは、駆動輪および従動輪の個数および位置を任意に設定／変更することが可能な、いわゆる四輪独立駆動方式の（電気）自動車である。 The vehicle V according to the embodiment is a so-called four-wheel independent drive type (electric) vehicle in which the number and positions of the drive wheels and the driven wheels can be arbitrarily set / changed.

すなわち、車両Ｖは、４つの車輪１０にそれぞれ対応するように設けられた４つの駆動装置２０を備えており、各駆動装置２０は、対応する車輪１０を独立に駆動可能ないわゆるインホイールモータとして構成されている。駆動装置２０は、対応する車輪１０に駆動力を与えることで当該車輪１０を駆動輪として駆動させることが可能であるとともに、対応する車輪１０に与える駆動力を停止することで当該車輪１０を従動輪として従動させることが可能である。 That is, the vehicle V includes four drive devices 20 provided so as to correspond to the four wheels 10, and each drive device 20 serves as a so-called in-wheel motor capable of independently driving the corresponding wheels 10. It is configured. The driving device 20 can drive the wheel 10 as a driving wheel by applying a driving force to the corresponding wheel 10, and also causes the wheel 10 to be driven by stopping the driving force applied to the corresponding wheel 10. It can be driven as a driving wheel.

より具体的に、前輪１０ＦＬに対応するように設けられた駆動装置２０ＦＬは、前輪１０ＦＬを駆動輪として駆動させたり従動輪として従動させたりすることが可能であり、前輪１０ＦＲに対応するように設けられた駆動装置２０ＦＲは、前輪１０ＦＲを駆動輪として駆動させたり従動輪として従動させたりすることが可能である。同様に、後輪１０ＲＬに対応するように設けられた駆動装置２０ＲＬは、後輪１０ＲＬを駆動輪として駆動させたり従動輪として従動させたりすることが可能であり、後輪１０ＲＲに対応するように設けられた駆動装置２０ＲＲは、後輪１０ＲＲを駆動輪として駆動させたり従動輪として従動させたりすることが可能である。 More specifically, the drive device 20FL provided so as to correspond to the front wheel 10FL can drive the front wheel 10FL as a driving wheel or a driven wheel, and is provided so as to correspond to the front wheel 10FR. The drive device 20FR can drive the front wheels 10FR as drive wheels or drive as driven wheels. Similarly, the drive device 20RL provided so as to correspond to the rear wheel 10RL can drive the rear wheel 10RL as a driving wheel or as a driven wheel, so as to correspond to the rear wheel 10RR. The provided drive device 20RR can drive the rear wheel 10RR as a driving wheel or a driven wheel.

また、車両Ｖは、上述した各駆動装置２０を統括的に制御する制御装置であるＥＣＵ（Ｅｌｅｃｔｒｏｎｉｃ Ｃｏｎｔｒｏｌ Ｕｎｉｔ）１００を備えている。ＥＣＵ１００は、たとえば、プロセッサ１０１やメモリ１０２や入出力装置（不図示）などといった、通常のコンピュータと同様のハードウェアを有したマイクロコンピュータとして構成される。 Further, the vehicle V includes an ECU (Electronic Control Unit) 100 which is a control device that collectively controls each of the above-mentioned drive devices 20. The ECU 100 is configured as a microcomputer having hardware similar to that of a normal computer, such as a processor 101, a memory 102, an input / output device (not shown), and the like.

なお、図１に示される例では、ＥＣＵ１００の制御対象として、駆動装置２０の他に、通知部４０が例示されている。詳細は後述するが、通知部４０は、車両Ｖの乗員に対して画像または音声（またはそれらの併用）により情報を通知するための情報出力装置である。 In the example shown in FIG. 1, the notification unit 40 is exemplified in addition to the drive device 20 as the control target of the ECU 100. Although the details will be described later, the notification unit 40 is an information output device for notifying the occupants of the vehicle V of information by image or voice (or a combination thereof).

ここで、ＥＣＵ１００は、車両Ｖの走行状態を検出するために車両Ｖに設けられる各種の車載センサの検出結果を制御に利用することが可能である。たとえば、図１に示される例では、車載センサの一つとして、車輪１０の回転速度を検出する車輪速センサ３１が設けられている。 Here, the ECU 100 can use the detection results of various in-vehicle sensors provided in the vehicle V for control in order to detect the traveling state of the vehicle V. For example, in the example shown in FIG. 1, a wheel speed sensor 31 that detects the rotational speed of the wheel 10 is provided as one of the in-vehicle sensors.

車輪速センサ３１は、複数の車輪１０に対応するように複数設けられる。すなわち、車輪速センサ３１は、前輪１０ＦＬの回転速度を検出する車輪速センサ３１ＦＬと、前輪１０ＦＲの回転速度を検出する車輪速センサ３１ＦＲと、後輪ＲＬの回転速度を検出する車輪速センサ３１ＲＬと、後輪ＲＲの回転速度を検出する車輪速センサ３１ＲＲと、の４つ設けられている。 A plurality of wheel speed sensors 31 are provided so as to correspond to the plurality of wheels 10. That is, the wheel speed sensor 31 includes a wheel speed sensor 31FL that detects the rotation speed of the front wheel 10FL, a wheel speed sensor 31FR that detects the rotation speed of the front wheel 10FR, and a wheel speed sensor 31RL that detects the rotation speed of the rear wheel RL. , And a wheel speed sensor 31RR that detects the rotation speed of the rear wheel RR, and four are provided.

なお、実施形態において、ＥＣＵ１００は、車輪速センサ３１以外の他の車載センサの検出結果も制御に利用することが可能である。詳細は後述するが、実施形態において、ＥＣＵ１００は、車両Ｖに対する操舵操作（の量）を検出する、すなわち車両Ｖが直進しているか旋回しているかを検出する車載センサとしての操舵センサ３２の検出結果と、車両Ｖが走行している路面の勾配を検出する、すなわち車両Ｖが勾配のある路面を走行しているか否かを検出する車載センサとしての勾配センサ３３の検出結果と、を制御に利用しうる。 In the embodiment, the ECU 100 can also use the detection results of the vehicle-mounted sensor other than the wheel speed sensor 31 for control. Although details will be described later, in the embodiment, the ECU 100 detects (amount) of the steering operation with respect to the vehicle V, that is, the detection of the steering sensor 32 as an in-vehicle sensor for detecting whether the vehicle V is traveling straight or turning. To control the result and the detection result of the gradient sensor 33 as an in-vehicle sensor that detects the slope of the road surface on which the vehicle V is traveling, that is, whether or not the vehicle V is traveling on the sloped road surface. Can be used.

ところで、従来から、車両が走行する路面の摩擦係数を求める技術について検討されている。このような技術として、たとえば、駆動輪として駆動する２つの車輪と、従動輪として従動する２つの車輪と、が予め決められた二輪駆動方式の車両において、駆動輪として駆動する２つの車輪の回転速度の平均値と、従動輪として駆動する２つの車輪の回転速度の平均値と、に基づいてスリップ比を算出し、当該スリップ比に基づいて路面の摩擦係数を推定する技術が知られている。 By the way, conventionally, a technique for obtaining the friction coefficient of the road surface on which a vehicle travels has been studied. As such a technique, for example, in a vehicle of a two-wheel drive system in which two wheels driven as driving wheels and two wheels driven as driven wheels are determined in advance, rotation of the two wheels driven as driving wheels A technique is known in which a slip ratio is calculated based on an average value of speeds and an average value of rotation speeds of two wheels driven as driven wheels, and a friction coefficient of a road surface is estimated based on the slip ratio. ..

しかしながら、上記のような従来の技術は、駆動輪および従動輪の個数および位置が固定であることが前提となっているので、駆動輪および従動輪の個数および位置が様々に変化しうる実施形態のような四輪独立駆動方式の車両Ｖにそのまま適用することができない。 However, since the conventional technique as described above is based on the premise that the number and positions of the driving wheels and the driven wheels are fixed, the number and positions of the driving wheels and the driven wheels can be changed in various ways. It cannot be applied as it is to a vehicle V having a four-wheel independent drive system such as.

そこで、実施形態は、以下に説明するような機能を有した路面状態推定装置２００をＥＣＵ１００内に実現することで、四輪独立駆動方式の車両Ｖを利用して路面の摩擦係数を適切に推定することを実現する。 Therefore, in the embodiment, by realizing the road surface condition estimation device 200 having the functions described below in the ECU 100, the friction coefficient of the road surface is appropriately estimated by using the vehicle V of the four-wheel independent drive system. Achieve what you do.

図２は、実施形態にかかる路面状態推定装置２００の機能を示した例示的かつ模式的なブロック図である。なお、実施形態において、路面状態は、基本的には路面の摩擦係数を意味するので、「路面状態推定装置」は、「路面摩擦係数推定装置」と言い換えてもよい。 FIG. 2 is an exemplary and schematic block diagram showing the function of the road surface condition estimation device 200 according to the embodiment. In the embodiment, the road surface condition basically means the friction coefficient of the road surface, so the “road surface condition estimation device” may be paraphrased as the “road surface friction coefficient estimation device”.

図２に示されるように、路面状態推定装置２００は、制御部２０１と、取得部２０２と、推定部２０３と、出力部２０４と、を備えている。これらの機能は、たとえば、ＥＣＵ１００のプロセッサ１０１がメモリ１０２に記憶されたプログラムを読み出して実行した結果として実現される。なお、実施形態では、これらの機能の一部または全部が、専用のハードウェア（回路）のみによって実現されてもよい。 As shown in FIG. 2, the road surface condition estimation device 200 includes a control unit 201, an acquisition unit 202, an estimation unit 203, and an output unit 204. These functions are realized, for example, as a result of the processor 101 of the ECU 100 reading and executing the program stored in the memory 102. In the embodiment, some or all of these functions may be realized only by dedicated hardware (circuit).

制御部２０１は、４つの駆動装置２０の各々に適宜指令値を出力し、車両Ｖに設けられた４つの車輪１０のうち一部が駆動輪として駆動し、残りの一部が従動輪として従動するように、４つの駆動装置２０を制御する。なお、実施形態において、制御部２０１は、４つの車輪１０の全てが駆動輪として駆動するように４つの駆動装置２０を制御することも可能であるが、路面の摩擦係数を推定するためには、少なくとも１つの車輪が従動輪として従動している必要がある。 The control unit 201 outputs command values to each of the four drive devices 20 as appropriate, and some of the four wheels 10 provided on the vehicle V are driven as drive wheels, and the remaining part is driven as a driven wheel. The four drive devices 20 are controlled so as to do so. In the embodiment, the control unit 201 can control the four drive devices 20 so that all the four wheels 10 are driven as drive wheels, but in order to estimate the friction coefficient of the road surface, , At least one wheel needs to be driven as a driven wheel.

取得部２０２は、車載センサとしての４つの車輪速センサ３１、操舵センサ３２、および勾配センサ３３の検出結果を取得する。 The acquisition unit 202 acquires the detection results of the four wheel speed sensors 31, the steering sensor 32, and the gradient sensor 33 as in-vehicle sensors.

推定部２０３は、４つの車輪速センサのうち駆動輪の回転速度を検出する第１の車輪速センサの検出結果と、４つの車輪速センサのうち従動輪の回転速度を検出する第２の車輪速センサの検出結果と、に基づいて、駆動輪ごとにスリップ比を算出し、当該スリップ比に基づいて、路面の摩擦係数を、駆動輪に対応した領域ごとに推定する。すなわち、推定部２０３は、駆動輪および従動輪の個数および位置がどのように設定されている場合であっても、路面上における駆動輪に対応した１以上の領域の各々の１以上の摩擦係数を推定する。 The estimation unit 203 detects the detection result of the first wheel speed sensor that detects the rotation speed of the driving wheel among the four wheel speed sensors, and the second wheel that detects the rotation speed of the driven wheel among the four wheel speed sensors. The slip ratio is calculated for each drive wheel based on the detection result of the speed sensor, and the friction coefficient of the road surface is estimated for each region corresponding to the drive wheels based on the slip ratio. That is, the estimation unit 203 has a friction coefficient of 1 or more for each of the 1 or more regions corresponding to the drive wheels on the road surface, regardless of how the number and positions of the drive wheels and the driven wheels are set. To estimate.

たとえば、推定部２０３は、駆動輪および従動輪がそれぞれ２つずつ存在する場合、２つの第１の車輪速センサの検出結果に基づいて取得される２つの駆動輪の各々の回転速度と、２つの第２の車輪速センサの検出結果に基づいて取得される２つの従動輪の回転速度の平均値と、に基づいて２つのスリップ比を算出し、当該２つのスリップ比に基づいて、路面上における２つの駆動輪に対応した２つの領域の各々の摩擦係数を推定する。 For example, when the estimation unit 203 has two drive wheels and two driven wheels, the rotation speed of each of the two drive wheels acquired based on the detection results of the two first wheel speed sensors and 2 Two slip ratios are calculated based on the average value of the rotational speeds of the two driving wheels acquired based on the detection results of the two second wheel speed sensors, and on the road surface based on the two slip ratios. Estimate the friction coefficient of each of the two regions corresponding to the two drive wheels in.

また、推定部２０３は、駆動輪が１つで従動輪が３つ存在する場合、１つの第１の車輪速センサの検出結果に基づいて取得される１つの駆動輪の回転速度と、３つの第２の車輪速センサの検出結果に基づいて取得される３つの従動輪の回転速度の平均値と、に基づいて、１つのスリップ比を算出し、当該１つのスリップ比に基づいて、路面上における１つの駆動輪に対応した１つの領域の摩擦係数を推定する。 Further, when the estimation unit 203 has one drive wheel and three driven wheels, the estimation unit 203 includes the rotation speed of one drive wheel and three driven wheels acquired based on the detection result of one first wheel speed sensor. One slip ratio is calculated based on the average value of the rotation speeds of the three driven wheels acquired based on the detection result of the second wheel speed sensor, and based on the one slip ratio, on the road surface. Estimate the friction coefficient of one region corresponding to one drive wheel in.

さらに、推定部２０３は、駆動輪が３つで従動輪が１つ存在する場合、３つの第１の車輪速センサの検出結果に基づいて取得される３つの駆動輪の各々の回転速度と、１つの第２の車輪速センサの検出結果に基づいて取得される１つの従動輪の回転速度と、に基づいて、３つのスリップ比を算出し、当該３つのスリップ比に基づいて、路面上における３つの駆動輪に対応した３つの領域の各々の摩擦係数を推定する。 Further, the estimation unit 203 determines the rotation speed of each of the three drive wheels acquired based on the detection results of the three first wheel speed sensors when there are three drive wheels and one trailing wheel. Three slip ratios are calculated based on the rotation speed of one driving wheel acquired based on the detection result of one second wheel speed sensor, and based on the three slip ratios, on the road surface. Estimate the friction coefficient of each of the three regions corresponding to the three drive wheels.

このように、実施形態において、摩擦係数は、路面上における駆動輪に対応した領域ごとに推定される。したがって、実施形態によれば、摩擦係数を複数回推定し、各摩擦係数を各領域の位置と対応付けることで、路面の状態をより細かく把握することが可能である。 Thus, in the embodiment, the coefficient of friction is estimated for each region corresponding to the drive wheels on the road surface. Therefore, according to the embodiment, it is possible to grasp the state of the road surface in more detail by estimating the friction coefficient a plurality of times and associating each friction coefficient with the position of each region.

そこで、実施形態において、推定部２０３は、情報を記憶するための記憶部２０３ａを有しており、自身で推定した摩擦係数を、路面上における駆動輪に対応した領域の位置に関する位置情報と対応付けて記憶部２０３ａに記憶する。位置情報は、たとえば車載センサの検出結果を利用したオドメトリなどに基づいて推定される車両Ｖの位置に基づいて取得される。 Therefore, in the embodiment, the estimation unit 203 has a storage unit 203a for storing information, and the friction coefficient estimated by itself corresponds to the position information regarding the position of the region corresponding to the drive wheel on the road surface. It is attached and stored in the storage unit 203a. The position information is acquired based on the position of the vehicle V estimated based on, for example, odometry using the detection result of the vehicle-mounted sensor.

図３は、実施形態にかかる摩擦係数が記憶部２０３ａに記憶される態様の一例を示した例示的かつ模式的な図である。図３に示されるように、推定部２０３により推定された摩擦係数は、（路面上における駆動輪に対応した領域の）位置と対応付けられた状態で記憶部２０３ａに記憶される。 FIG. 3 is an exemplary and schematic diagram showing an example of a mode in which the friction coefficient according to the embodiment is stored in the storage unit 203a. As shown in FIG. 3, the coefficient of friction estimated by the estimation unit 203 is stored in the storage unit 203a in a state associated with the position (in the region corresponding to the drive wheels on the road surface).

なお、図３に示される例では、摩擦係数Ｋｘと位置Ｐｘとの対応関係のみが例示されているが、実施形態では、Ｋｘ以外の摩擦係数とＰｘ以外の位置との対応関係も記憶されうる。また、実施形態では、たとえば同じ位置の領域に対応した摩擦係数が複数回推定された場合、最新の摩擦係数を考慮して古い摩擦係数を補正したり、最新の摩擦係数で古い摩擦係数が更新したりすることで、摩擦係数の推定精度が高められうる。 In the example shown in FIG. 3, only the correspondence between the friction coefficient Kx and the position Px is illustrated, but in the embodiment, the correspondence between the friction coefficient other than Kx and the position other than Px can also be stored. .. Further, in the embodiment, for example, when the friction coefficient corresponding to the region at the same position is estimated multiple times, the old friction coefficient is corrected in consideration of the latest friction coefficient, or the old friction coefficient is updated with the latest friction coefficient. By doing so, the estimation accuracy of the coefficient of friction can be improved.

また、実施形態では、摩擦係数と位置との対応関係が推定部２０３内の記憶部２０３ａに記憶される構成が例示されているが、摩擦係数と位置との対応関係を記憶する手段は、推定部２０３の外に設けられてもよい。たとえば、実施形態では、路面状態推定装置２００に通信機能を持たせ、当該通信機能により、摩擦係数と位置との対応関係を、ネットワーク上に記憶部として設けられたサーバに送信して記憶させてもよい。このような構成によれば、たとえば、複数の車両Ｖで推定された摩擦係数を対応する位置とともにネットワーク上のサーバに集めて管理することが可能である。 Further, in the embodiment, a configuration in which the correspondence between the friction coefficient and the position is stored in the storage unit 203a in the estimation unit 203 is exemplified, but the means for storing the correspondence between the friction coefficient and the position is estimated. It may be provided outside the portion 203. For example, in the embodiment, the road surface condition estimation device 200 is provided with a communication function, and the communication function transmits and stores the correspondence between the friction coefficient and the position to a server provided as a storage unit on the network. May be good. According to such a configuration, for example, it is possible to collect and manage the friction coefficients estimated by a plurality of vehicles V in a server on the network together with the corresponding positions.

図２に戻り、出力部２０４は、推定部２０３により推定された摩擦係数と閾値との比較結果に応じて、通知部４０を介して所定の通知を出力する。たとえば、出力部２０４は、推定部２０３により推定された１以上の摩擦係数のうち少なくとも１つが閾値より小さい場合、通知部４０を介して、路面（のうち少なくとも一部の領域）が滑りやすくなっている旨の警報を表す通知を車両Ｖの乗員に出力する。 Returning to FIG. 2, the output unit 204 outputs a predetermined notification via the notification unit 40 according to the comparison result between the friction coefficient estimated by the estimation unit 203 and the threshold value. For example, in the output unit 204, when at least one of the friction coefficients of 1 or more estimated by the estimation unit 203 is smaller than the threshold value, the road surface (at least a part of the region) becomes slippery via the notification unit 40. A notification indicating an alarm indicating that the vehicle V is being output is output to the occupant of the vehicle V.

ところで、実施形態では、前述したように、駆動輪および従動輪の個数および位置を任意に設定／変更することが可能である。したがって、実施形態では、たとえば以下に図４〜図７に示されるような形で、駆動輪および従動輪の個数および位置の設定を車両Ｖの走行状態に応じて適宜変化させれば、車両Ｖの挙動の安定化を図りながら摩擦係数の適切な推定を実現することが可能である。 By the way, in the embodiment, as described above, the number and position of the driving wheels and the driven wheels can be arbitrarily set / changed. Therefore, in the embodiment, if the setting of the number and position of the driving wheels and the driven wheels is appropriately changed according to the traveling state of the vehicle V, for example, as shown in FIGS. 4 to 7 below, the vehicle V It is possible to realize an appropriate estimation of the friction coefficient while stabilizing the behavior of.

図４は、実施形態おいて実現されうる駆動輪および従動輪の設定の第１の例を示した例示的かつ模式的な図である。以下に説明するように、図４に示される設定は、車両Ｖが路面としての傾斜面を上る方向に進む場合（矢印Ａ４０１参照）において特に有効であるが、他の場合（たとえば車両Ｖが平坦路を通常通りに走行する場合）にも有効である。なお、車両Ｖが傾斜面を上る方向に進むか否かは、勾配センサ３３の検出結果などに基づいて取得することが可能である。 FIG. 4 is an exemplary and schematic diagram showing a first example of driving and trailing wheel settings that can be realized in an embodiment. As described below, the settings shown in FIG. 4 are particularly effective when the vehicle V travels up an inclined surface as a road surface (see arrow A401), but in other cases (for example, the vehicle V is flat). It is also effective when traveling on the road as usual). Whether or not the vehicle V advances in the direction of climbing the inclined surface can be acquired based on the detection result of the gradient sensor 33 or the like.

車両Ｖが傾斜面を上る方向に進む場合、車両Ｖの進行方向の後側に設けられた後側車輪としての後輪１０ＲＬおよび１０ＲＲを駆動輪として駆動するよりも、車両Ｖの進行方向の前側に設けられた前側車輪としての前輪１０ＦＬおよび１０ＦＲを駆動輪として駆動した方が、車両Ｖを前から引っ張る形で駆動力が発生し、車両Ｖのふらつき（回転）を抑制することが可能だと考えられる。したがって、この場合、制御部２０１は、前輪１０ＦＬおよび１０ＦＲが駆動輪として駆動し、後輪１０ＲＬおよび１０ＲＲが従動輪として従動するように、駆動装置２０を制御する。これにより、車両Ｖの挙動の安定化を図りながら、路面上における後輪１０ＲＬおよび１０ＲＲに対応した各領域の摩擦係数を適切に推定することが可能である。 When the vehicle V advances in the direction of going up the inclined surface, the front side in the traveling direction of the vehicle V is driven rather than driving the rear wheels 10RL and 10RR as the rear wheels provided on the rear side in the traveling direction of the vehicle V as driving wheels. By driving the front wheels 10FL and 10FR as the front wheels provided in the above as driving wheels, the driving force is generated by pulling the vehicle V from the front, and it is possible to suppress the wobbling (rotation) of the vehicle V. Conceivable. Therefore, in this case, the control unit 201 controls the drive device 20 so that the front wheels 10FL and 10FR are driven as drive wheels and the rear wheels 10RL and 10RR are driven as driven wheels. As a result, it is possible to appropriately estimate the friction coefficient of each region corresponding to the rear wheels 10RL and 10RR on the road surface while stabilizing the behavior of the vehicle V.

なお、実施形態では、前輪１０ＦＬおよび１０ＦＲの方が後輪１０ＲＬおよび１０ＲＲよりも数多く駆動輪として駆動しさえすれば、図４に示される設定以外の設定によっても、車両Ｖが傾斜面を上る方向に進む場合に上記と同様の効果を得ることが可能である。このような設定の一例として、たとえば、前輪１０ＦＬおよび１０ＦＲと、後輪１０ＲＬおよび１０ＲＲのうち一方と、の３つが駆動輪として駆動し、後輪１０ＲＬおよび１０ＲＲのうち他方のみが従動輪として従動するという設定が考えられる。 In the embodiment, as long as the front wheels 10FL and 10FR are driven as more driving wheels than the rear wheels 10RL and 10RR, the vehicle V goes up the inclined surface even with a setting other than the setting shown in FIG. It is possible to obtain the same effect as described above when proceeding to. As an example of such a setting, for example, three of the front wheels 10FL and 10FR and one of the rear wheels 10RL and 10RR are driven as driving wheels, and only the other of the rear wheels 10RL and 10RR is driven as a driven wheel. Can be considered.

図５は、実施形態おいて実現されうる駆動輪および従動輪の設定の第２の例を示した例示的かつ模式的な図である。図５に示される設定は、図４に示される設定を前後反転したものに相当する。したがって、図５に示される設定は、車両Ｖが路面としての傾斜面を下る方向に進む場合（矢印Ａ５０１参照）において有効であるが、他の場合（たとえば車両Ｖが平坦路を通常通りに走行する場合）にも有効である。 FIG. 5 is an exemplary and schematic diagram showing a second example of driving and trailing wheel settings that can be realized in an embodiment. The settings shown in FIG. 5 correspond to the settings shown in FIG. 4 inverted back and forth. Therefore, the setting shown in FIG. 5 is effective when the vehicle V travels down the inclined surface as the road surface (see arrow A501), but in other cases (for example, the vehicle V travels on a flat road as usual). It is also effective when doing).

より具体的に、車両Ｖが傾斜面を下る方向に進む場合、車両Ｖの進行方向の前側に設けられた前側車輪としての前輪１０ＦＬおよび１０ＦＲを駆動輪として駆動するよりも、車両Ｖの進行方向の後側に設けられた後側車輪としての後輪１０ＲＬおよび１０ＲＲを駆動輪として駆動した方が、たとえば回生ブレーキをかけた際に車両Ｖを後ろから引っ張る形で制動力が発生し、車両Ｖのふらつき（回転）を抑制することが可能だと考えられる。したがって、この場合、制御部２０１は、後輪１０ＲＬおよび１０ＲＲが駆動輪として駆動し、前輪１０ＦＬおよび１０ＦＲが従動輪として従動するように、駆動装置２０を制御する。これにより、車両Ｖの挙動の安定化を図りながら、路面上における前輪１０ＦＬおよび１０ＦＲに対応した各領域の摩擦係数を適切に推定することが可能である。 More specifically, when the vehicle V advances in the direction of going down the inclined surface, the traveling direction of the vehicle V is more than driving the front wheels 10FL and 10FR as the front wheels provided on the front side of the traveling direction of the vehicle V as driving wheels. When the rear wheels 10RL and 10RR as the rear wheels provided on the rear side are driven as the driving wheels, for example, when the regenerative brake is applied, a braking force is generated by pulling the vehicle V from behind, and the vehicle V is generated. It is thought that it is possible to suppress the wobbling (rotation) of the wheel. Therefore, in this case, the control unit 201 controls the drive device 20 so that the rear wheels 10RL and 10RR are driven as driving wheels and the front wheels 10FL and 10FR are driven as driven wheels. As a result, it is possible to appropriately estimate the friction coefficient of each region corresponding to the front wheels 10FL and 10FR on the road surface while stabilizing the behavior of the vehicle V.

なお、実施形態では、後輪１０ＲＬおよび１０ＲＲの方が前輪１０ＦＬおよび１０ＦＲよりも数多く駆動輪として駆動しさえすれば、図５に示される設定以外の設定によっても、車両Ｖが傾斜面を下る方向に進む場合に上記と同様の効果を得ることが可能である。このような設定の一例として、たとえば、後輪１０ＲＬおよび１０ＲＲと、前輪１０ＦＬおよび１０ＦＲのうち一方と、の３つが駆動輪として駆動し、前輪１０ＦＬおよび１０ＦＲのうち他方のみが従動輪として従動するという設定が考えられる。 In the embodiment, as long as the rear wheels 10RL and 10RR are driven as more driving wheels than the front wheels 10FL and 10FR, the vehicle V goes down the inclined surface even with a setting other than the setting shown in FIG. It is possible to obtain the same effect as described above when proceeding to. As an example of such a setting, for example, three of the rear wheels 10RL and 10RR and one of the front wheels 10FL and 10FR are driven as driving wheels, and only the other of the front wheels 10FL and 10FR is driven as a driven wheel. Settings are possible.

図６は、実施形態おいて実現されうる駆動輪および従動輪の設定の第３の例を示した例示的かつ模式的な図である。以下に説明するように、図６に示される設定は、車両Ｖが右回りに旋回を行う場合（矢印Ａ６０１参照）において有効である。なお、車両Ｖが右回りに旋回を行うか否かは、操舵センサ３２の検出結果などに基づいて取得することが可能である。 FIG. 6 is an exemplary and schematic diagram showing a third example of driving and trailing wheel settings that can be realized in an embodiment. As described below, the settings shown in FIG. 6 are effective when the vehicle V makes a clockwise turn (see arrow A601). Whether or not the vehicle V turns clockwise can be obtained based on the detection result of the steering sensor 32 or the like.

車両Ｖが右回りに旋回する場合、旋回の外側に設けられた外側車輪としての前輪１０ＦＬおよび後輪１０ＲＬに、旋回の内側に設けられた内側車輪としての前輪１０ＦＲおよび後輪１０ＲＲよりも大きな駆動力が発生すれば、車両Ｖがスムーズに旋回する。したがって、この場合、制御部２０１は、両方の外側車輪としての前輪１０ＦＬおよび後輪１０ＲＬと、一方の内側車輪としての前輪ＦＲと、が駆動輪として駆動し、他方の内側車輪としての後輪１０ＲＲが従動輪として従動するように、駆動装置２０を制御する。これにより、右回りの旋回の際の車両Ｖの挙動の安定化を図りながら、路面上における前輪１０ＦＬ、前輪１０ＦＲ、および後輪１０ＲＬに対応した各領域の摩擦係数を適切に推定することが可能である。 When the vehicle V turns clockwise, the front wheels 10FL and rear wheels 10RL as outer wheels provided outside the turn are driven larger than the front wheels 10FR and rear wheels 10RR as inner wheels provided inside the turn. If a force is generated, the vehicle V turns smoothly. Therefore, in this case, the control unit 201 is driven by the front wheels 10FL and the rear wheels 10RL as both outer wheels and the front wheels FR as one inner wheel as driving wheels, and the rear wheels 10RR as the other inner wheels. Controls the drive device 20 so that the drive wheel is driven as a driven wheel. As a result, it is possible to appropriately estimate the friction coefficient of each region corresponding to the front wheels 10FL, the front wheels 10FR, and the rear wheels 10RL on the road surface while stabilizing the behavior of the vehicle V when turning clockwise. Is.

なお、実施形態では、外側車輪としての前輪１０ＦＬおよび後輪１０ＲＬの方が内側車輪としての前輪１０ＦＲおよび後輪１０ＲＲよりも数多く駆動輪として駆動しさえすれば、図６に示される設定以外の設定によっても、車両Ｖが右回りに旋回する場合に上記と同様の効果を得ることが可能である。このような設定の一例として、たとえば、外側車輪としての前輪１０ＦＬおよび後輪１０ＲＬのみが駆動輪として駆動し、内側車輪としての前輪１０ＦＲおよび後輪１０ＲＲは従動輪として従動するという設定が考えられる。 In the embodiment, as long as the front wheels 10FL and the rear wheels 10RL as the outer wheels are driven as more drive wheels than the front wheels 10FR and the rear wheels 10RR as the inner wheels, the settings other than those shown in FIG. 6 are set. It is also possible to obtain the same effect as described above when the vehicle V turns clockwise. As an example of such a setting, for example, it is conceivable that only the front wheels 10FL and the rear wheels 10RL as the outer wheels are driven as the driving wheels, and the front wheels 10FR and the rear wheels 10RR as the inner wheels are driven as the driven wheels.

ここで、図６に示される設定は、車両Ｖが右回りに旋回する場合のみならず、車両Ｖが直進する場合（矢印Ａ６０２参照）においても有効である。なお、車両Ｖが直進するか否かは、操舵センサ３２の検出結果などに基づいて取得することが可能である。 Here, the setting shown in FIG. 6 is effective not only when the vehicle V turns clockwise but also when the vehicle V goes straight (see arrow A602). Whether or not the vehicle V travels straight can be obtained based on the detection result of the steering sensor 32 or the like.

より具体的に、図６に示される設定においては、車両Ｖの左右方向の一方側としての左側で進行方向に沿って設けられた一方車輪としての前輪１０ＦＬおよび後輪１０ＲＬの両方が駆動輪として駆動する。したがって、図６に示される設定によれば、車両Ｖが直進する場合において、駆動輪として駆動する前輪１０ＦＬおよび後輪１０ＲＬにより、路面上における同じ位置（領域）の摩擦係数を２回推定することが可能であるので、摩擦係数の推定精度を高めることが可能である。 More specifically, in the setting shown in FIG. 6, both the front wheel 10FL and the rear wheel 10RL as one wheel provided along the traveling direction on the left side as one side in the left-right direction of the vehicle V are used as driving wheels. Drive. Therefore, according to the setting shown in FIG. 6, when the vehicle V travels straight, the friction coefficient at the same position (region) on the road surface is estimated twice by the front wheels 10FL and the rear wheels 10RL driven as driving wheels. Therefore, it is possible to improve the estimation accuracy of the friction coefficient.

図７は、実施形態おいて実現されうる駆動輪および従動輪の設定の第４の例を示した例示的かつ模式的な図である。図７に示される設定は、図６に示される設定を左右反転したものに相当する。したがって、図７に示される設定は、車両Ｖが左回りに旋回を行う場合（矢印Ａ７０１参照）において有効である。 FIG. 7 is an exemplary and schematic diagram showing a fourth example of driving and trailing wheel settings that can be realized in an embodiment. The settings shown in FIG. 7 correspond to the left-right reversals of the settings shown in FIG. Therefore, the setting shown in FIG. 7 is effective when the vehicle V turns counterclockwise (see arrow A701).

より具体的に、車両Ｖが左回りに旋回する場合、旋回の外側に設けられた外側車輪としての前輪１０ＦＲおよび後輪１０ＲＲに、旋回の内側に設けられた内側車輪としての前輪１０ＦＬおよび後輪１０ＲＬよりも大きな駆動力が発生すれば、車両Ｖがスムーズに旋回する。したがって、この場合、制御部２０１は、両方の外側車輪としての前輪１０ＦＲおよび後輪１０ＲＲと、一方の内側車輪としての前輪ＦＬと、が駆動輪として駆動し、他方の内側車輪としての後輪１０ＲＬが従動輪として従動するように、駆動装置２０を制御する。これにより、左回りの旋回の際の車両Ｖの挙動の安定化を図りながら、路面上における前輪１０ＦＬ、前輪１０ＦＲ、および後輪１０ＲＲに対応した各領域の摩擦係数を適切に推定することが可能である。 More specifically, when the vehicle V turns counterclockwise, the front wheels 10FR and rear wheels 10RR as outer wheels provided outside the turn, and the front wheels 10FL and rear wheels as inner wheels provided inside the turn. If a driving force larger than 10 RL is generated, the vehicle V turns smoothly. Therefore, in this case, the control unit 201 is driven by the front wheels 10FR and the rear wheels 10RR as both outer wheels and the front wheels FL as one inner wheel as drive wheels, and the rear wheels 10RL as the other inner wheels. Controls the drive device 20 so that the drive wheel is driven as a driven wheel. This makes it possible to appropriately estimate the friction coefficient of each region corresponding to the front wheels 10FL, front wheels 10FR, and rear wheels 10RR on the road surface while stabilizing the behavior of the vehicle V when turning counterclockwise. Is.

なお、実施形態では、外側車輪としての前輪１０ＦＲおよび後輪１０ＲＲの方が内側車輪としての前輪１０ＦＬおよび後輪１０ＲＬよりも数多く駆動輪として駆動しさえすれば、図７に示される設定以外の設定によっても、車両Ｖが左回りに旋回する場合に上記と同様の効果を得ることが可能である。このような設定の一例として、たとえば、外側車輪としての前輪１０ＦＲおよび後輪１０ＲＲのみが駆動輪として駆動し、内側車輪としての前輪１０ＦＬおよび後輪１０ＲＬは従動輪として従動するという設定が考えられる。 In the embodiment, as long as the front wheels 10FR and the rear wheels 10RR as the outer wheels are driven as more drive wheels than the front wheels 10FL and the rear wheels 10RL as the inner wheels, the settings other than those shown in FIG. 7 are set. It is also possible to obtain the same effect as described above when the vehicle V turns counterclockwise. As an example of such a setting, for example, it is conceivable that only the front wheels 10FR and the rear wheels 10RR as the outer wheels are driven as the driving wheels, and the front wheels 10FL and the rear wheels 10RL as the inner wheels are driven as the driven wheels.

ここで、図７に示される設定も、図６に示される設定と同様に、車両Ｖが直進する場合（矢印Ａ７０２参照）においても有効である。 Here, the setting shown in FIG. 7 is also effective when the vehicle V travels straight (see arrow A702), similarly to the setting shown in FIG.

より具体的に、図７に示される設定においてば、車両Ｖの左右方向の他方側としての右側で進行方向に沿って設けられた他方車輪としての前輪１０ＦＬおよび後輪１０ＲＬの両方が駆動輪として駆動する。したがって、図７に示される設定によれば、車両Ｖが直進する場合において、駆動輪として駆動する前輪１０ＦＲおよび後輪１０ＲＲにより、路面上における同じ位置（領域）の摩擦係数を２回推定することが可能であるので、摩擦係数の推定精度を高めることが可能である。 More specifically, in the setting shown in FIG. 7, both the front wheels 10FL and the rear wheels 10RL as the other wheels provided along the traveling direction on the right side as the other side in the left-right direction of the vehicle V are used as driving wheels. Drive. Therefore, according to the setting shown in FIG. 7, when the vehicle V travels straight, the friction coefficient of the same position (region) on the road surface is estimated twice by the front wheels 10FR and the rear wheels 10RR driven as driving wheels. Therefore, it is possible to improve the estimation accuracy of the friction coefficient.

ところで、図６および図７のいずれに示される設定においても、車両Ｖの左側の一方車輪と右側の他方車輪とが少なくとも１つずつ、より具体的には、前輪１０ＦＬおよび１０ＦＲが駆動輪として駆動する。したがって、これらの設定によれば、路面の摩擦係数として、路面上における一方車輪に対応した一方領域としての左側領域の摩擦係数である第１の摩擦係数と、路面上における他方車輪に対応した他方領域としての右側領域の摩擦係数である第２の摩擦係数と、を別個に推定することが可能である。 By the way, in any of the settings shown in FIGS. 6 and 7, at least one wheel on the left side and one wheel on the right side of the vehicle V are driven, more specifically, the front wheels 10FL and 10FR are driven as driving wheels. To do. Therefore, according to these settings, the coefficient of friction of the road surface is the first friction coefficient, which is the friction coefficient of the left region as one region corresponding to one wheel on the road surface, and the other corresponding to the other wheel on the road surface. It is possible to estimate separately from the second friction coefficient, which is the friction coefficient of the right region as the region.

上記を踏まえて、実施形態において、制御部２０１は、第１の摩擦係数と第２の摩擦係数との大小関係に応じて、一方車輪と他方車輪とのうちいずれを数多く駆動輪として駆動させるかを決定しうる。 Based on the above, in the embodiment, which of the one wheel and the other wheel is driven by the control unit 201 as a driving wheel according to the magnitude relationship between the first friction coefficient and the second friction coefficient. Can be determined.

すなわち、第１の摩擦係数が第２の摩擦係数よりも小さい場合、左側領域が、右側領域に比べて、駆動輪が一輪あたりに路面に伝達可能な駆動力が小さい滑りやすい領域だといえるので、左側領域に配置される一方車輪を右側領域に配置される他方車輪よりも数多く駆動輪として駆動した方が、左側領域の走行に必要な駆動力を分散して確保し、車両Ｖの挙動の安定化を図ることが可能である。したがって、この場合、制御部２０１は、図６に示される設定に基づき、一方車輪としての前輪１０ＦＬおよび後輪１０ＲＬの両方と、他方車輪のうちの１つとしての前輪１０ＦＲと、が駆動輪として駆動し、残りの他方車輪としての後輪ＲＲが従動輪として従動するように、駆動装置２０を制御する。 That is, when the first friction coefficient is smaller than the second friction coefficient, it can be said that the left side region is a slippery region in which the driving force that the driving wheels can transmit to the road surface per wheel is smaller than that of the right side region. If one wheel arranged in the left area is driven as more driving wheels than the other wheel arranged in the right area, the driving force required for traveling in the left area is dispersed and secured, and the behavior of the vehicle V is changed. It is possible to stabilize it. Therefore, in this case, the control unit 201 uses both the front wheels 10FL and the rear wheels 10RL as one wheel and the front wheels 10FR as one of the other wheels as driving wheels based on the settings shown in FIG. The drive device 20 is controlled so that the rear wheel RR as the remaining other wheel is driven as a driven wheel.

逆に、第１の摩擦係数が第２の摩擦係数よりも大きい場合、右側領域が、左側領域に比べて、駆動輪が一輪あたりに路面に伝達可能な駆動力が小さい滑りやすい領域だといえるので、右側領域に配置される他方車輪を左側領域に配置される一方車輪よりも数多く駆動輪として駆動した方が、右側領域の走行に必要な駆動力を分散して確保し、車両Ｖの挙動の安定化を図ることが可能である。したがって、この場合、制御部２０１は、図７に示される設定に基づき、他方車輪としての前輪１０ＦＲおよび後輪１０ＲＲの両方と、一方車輪のうちの１つとしての前輪１０ＦＬと、が駆動輪として駆動し、残りの他方車輪としての後輪ＲＬが従動輪として従動するように、駆動装置２０を制御する。 On the contrary, when the first friction coefficient is larger than the second friction coefficient, it can be said that the right side region is a slippery region in which the driving force that the driving wheels can transmit to the road surface per wheel is smaller than that of the left side region. Therefore, driving the other wheel arranged in the right side region as more driving wheels than the one wheel arranged in the left side region disperses and secures the driving force required for traveling in the right side region, and the behavior of the vehicle V. It is possible to stabilize the wheel. Therefore, in this case, based on the setting shown in FIG. 7, the control unit 201 uses both the front wheels 10FR and the rear wheels 10RR as the other wheels and the front wheels 10FL as one of the wheels as driving wheels. The drive device 20 is controlled so that the rear wheel RL as the remaining other wheel is driven as a driven wheel.

このように、実施形態において、制御部２０１は、車載センサの検出結果に応じて、たとえば図４〜図７に示される設定を適宜使い分けることで、駆動輪として駆動させる車輪１０と、従動輪として駆動させる車輪１０と、を車両Ｖの走行状態に適した形で決定することが可能である。 As described above, in the embodiment, the control unit 201 has the wheels 10 to be driven as the driving wheels and the driven wheels by appropriately using the settings shown in FIGS. 4 to 7, for example, according to the detection result of the vehicle-mounted sensor. It is possible to determine the wheels 10 to be driven in a form suitable for the traveling state of the vehicle V.

なお、実施形態では、車両Ｖとして四輪の自動車が例示されているが、実施形態の技術は、駆動装置によって独立に制御される複数の車輪が設けられた構成であれば、四輪の自動車以外の車両にも適用することが可能である。この場合、四輪の自動車以外の車両においても、駆動輪および従動輪の個数および位置の設定として、図４〜図７に示される設定を上記と同様の発想に基づいて適宜アレンジしたものを車両Ｖの走行状態に応じて使い分ければ、上記と同様の有効な結果が得られる。 In the embodiment, a four-wheeled vehicle is exemplified as the vehicle V, but the technology of the embodiment is a four-wheeled vehicle as long as it is provided with a plurality of wheels independently controlled by a driving device. It can be applied to vehicles other than the above. In this case, even in a vehicle other than a four-wheeled automobile, as the setting of the number and position of the driving wheel and the driven wheel, the setting shown in FIGS. 4 to 7 is appropriately arranged based on the same idea as described above. If it is used properly according to the traveling state of V, the same effective result as above can be obtained.

以上の構成に基づき、実施形態にかかる路面状態推定装置２００は、次の図８に示されるような流れに従って処理を実行する。 Based on the above configuration, the road surface condition estimation device 200 according to the embodiment executes the process according to the flow as shown in FIG. 8 below.

図８は、実施形態にかかる路面状態推定装置２００が路面の摩擦係数を推定するために実行する一連の処理を示した例示的かつ模式的なフローチャートである。図８に示される一連の処理は、車両Ｖが走行している間、繰り返し実行される。 FIG. 8 is an exemplary and schematic flowchart showing a series of processes executed by the road surface condition estimation device 200 according to the embodiment for estimating the friction coefficient of the road surface. The series of processes shown in FIG. 8 is repeatedly executed while the vehicle V is traveling.

図８に示されるように、実施形態では、まず、Ｓ８０１において、路面状態推定装置２００の取得部２０２は、車輪速センサ３１や操舵センサ３２や勾配センサ３３などを含む各種の車載センサの検出結果に基づいて、車両Ｖの走行状態を取得する。車両Ｖの走行状態とは、たとえば、車両Ｖが傾斜面を走行しているか否か、傾斜面における車両Ｖの走行方向が上り方向であるか下り方向であるか、車両Ｖが旋回を行っているか否か、および、車両Ｖが直進しているか否かなどを示す情報である。 As shown in FIG. 8, in the embodiment, first, in S801, the acquisition unit 202 of the road surface condition estimation device 200 detects the detection results of various in-vehicle sensors including the wheel speed sensor 31, the steering sensor 32, the gradient sensor 33, and the like. Based on, the traveling state of the vehicle V is acquired. The traveling state of the vehicle V is, for example, whether or not the vehicle V is traveling on an inclined surface, whether the traveling direction of the vehicle V on the inclined surface is an up direction or a down direction, and the vehicle V makes a turn. This is information indicating whether or not the vehicle V is traveling straight.

そして、Ｓ８０２において、路面状態推定装置２００の制御部２０１は、Ｓ８０１で取得された車両Ｖの走行状態に応じて、駆動輪／従動輪として機能させる車輪１０の個数および位置を決定し、決定内容に沿って駆動装置２０を制御する。 Then, in S802, the control unit 201 of the road surface condition estimation device 200 determines the number and positions of the wheels 10 to function as the driving wheels / trailing wheels according to the traveling state of the vehicle V acquired in S801, and the determined contents. The drive device 20 is controlled along the above.

そして、Ｓ８０３において、路面状態推定装置２００の取得部２０２は、各車輪速センサ３１の検出結果に基づいて、各車輪１０の回転速度を取得する。 Then, in S803, the acquisition unit 202 of the road surface condition estimation device 200 acquires the rotation speed of each wheel 10 based on the detection result of each wheel speed sensor 31.

そして、Ｓ８０４において、路面状態推定装置２００の推定部２０３は、Ｓ８０３で取得された情報に基づいて、前述したような方法により、駆動輪ごとにスリップ比を算出し、当該スリップ比に基づいて、路面上における駆動輪に対応した領域ごとに摩擦係数を推定する。 Then, in S804, the estimation unit 203 of the road surface condition estimation device 200 calculates the slip ratio for each drive wheel by the method as described above based on the information acquired in S803, and based on the slip ratio, The coefficient of friction is estimated for each region on the road surface corresponding to the drive wheels.

そして、Ｓ８０５において、路面状態推定装置２００の推定部２０３は、Ｓ８０４で推定された摩擦係数を、当該摩擦係数に従って摩擦を発生させると推定される領域、すなわちＳ８０４における摩擦係数の推定時における駆動輪に対応した路面上の領域の位置に関する位置情報と対応付けて記憶部２０３ａに記憶する。 Then, in S805, the estimation unit 203 of the road surface condition estimation device 200 uses the friction coefficient estimated in S804 as a driving wheel in a region estimated to generate friction according to the friction coefficient, that is, when the friction coefficient is estimated in S804. It is stored in the storage unit 203a in association with the position information regarding the position of the region on the road surface corresponding to.

そして、Ｓ８０６において、路面状態推定装置２００の出力部２０４は、Ｓ８０４における処理の結果、閾値よりも小さい摩擦係数が推定されたか否かを判断する。すなわち、出力部２０４は、Ｓ８０４で推定された１以上の摩擦係数のうち少なくとも１つが閾値より小さいか否かを判断する。 Then, in S806, the output unit 204 of the road surface condition estimation device 200 determines whether or not a friction coefficient smaller than the threshold value is estimated as a result of the processing in S804. That is, the output unit 204 determines whether or not at least one of the friction coefficients of 1 or more estimated in S804 is smaller than the threshold value.

Ｓ８０６において、閾値よりも小さい摩擦係数が推定されたと判断された場合、Ｓ８０７に処理が進む。そして、Ｓ８０７において、路面状態推定装置２００の出力部２０４は、通知部４０を介して、路面（のうち閾値よりも小さい摩擦係数に対応した少なくとも一部の領域）が滑りやすくなっている旨の警報を表す通知を車両Ｖの乗員に出力する。そして、処理が終了する。 If it is determined in S806 that a friction coefficient smaller than the threshold value is estimated, the process proceeds to S807. Then, in S807, the output unit 204 of the road surface condition estimation device 200 indicates that the road surface (at least a part of the region corresponding to the friction coefficient smaller than the threshold value) becomes slippery via the notification unit 40. A notification indicating an alarm is output to the occupant of the vehicle V. Then, the process ends.

なお、Ｓ８０６において、閾値よりも小さい摩擦係数が推定されなかったと判断された場合、Ｓ８０７に処理が進むことなく、そのまま処理が終了する。 If it is determined in S806 that a friction coefficient smaller than the threshold value has not been estimated, the process ends without proceeding to S807.

以上説明したように、実施形態にかかる路面状態推定装置２００は、制御部２０１と、取得部２０２と、推定部２０３と、を備えている。制御部２０１は、路面を走行する車両Ｖに設けられた複数の車輪１０のうち一部が駆動輪として駆動し、複数の車輪のうち残りの一部が従動輪として従動するように、複数の車輪をそれぞれ独立に駆動可能な駆動装置２０を制御する。取得部２０２は、複数の車輪１０の回転速度をそれぞれ検出する複数の車輪速センサ３１の検出結果を取得する。推定部２０３は、複数の車輪速センサ３１のうち駆動輪の回転速度を検出する第１の車輪速センサの検出結果と、複数の車輪速センサのうち従動輪の回転速度を検出する第２の車輪速センサの検出結果と、に基づいて、駆動輪ごとにスリップ比を算出し、当該スリップ比に基づいて、路面上における駆動輪に対応した領域ごとに摩擦係数を推定する。 As described above, the road surface condition estimation device 200 according to the embodiment includes a control unit 201, an acquisition unit 202, and an estimation unit 203. The control unit 201 has a plurality of wheels 10 provided on the vehicle V traveling on the road surface so that a part of the wheels 10 is driven as a driving wheel and the remaining part of the wheels is driven as a driven wheel. It controls a drive device 20 that can drive the wheels independently. The acquisition unit 202 acquires the detection results of the plurality of wheel speed sensors 31 that detect the rotation speeds of the plurality of wheels 10. The estimation unit 203 detects the detection result of the first wheel speed sensor that detects the rotation speed of the driving wheel among the plurality of wheel speed sensors 31, and the second wheel speed sensor that detects the rotation speed of the driven wheel among the plurality of wheel speed sensors. The slip ratio is calculated for each drive wheel based on the detection result of the wheel speed sensor, and the friction coefficient is estimated for each region corresponding to the drive wheels on the road surface based on the slip ratio.

実施形態によれば、上記のような構成に基づいて、四輪独立駆動方式の車両Ｖを利用して、駆動輪および従動輪の個数および位置に関わらず、路面の摩擦係数を、駆動輪に対応した領域ごとに適切に推定することができる。 According to the embodiment, based on the above configuration, the vehicle V of the four-wheel independent drive system is used to apply the friction coefficient of the road surface to the drive wheels regardless of the number and positions of the drive wheels and the driven wheels. It can be estimated appropriately for each corresponding area.

より具体的に、実施形態において、推定部２０３は、駆動輪および従動輪がそれぞれ複数存在する場合、第１の車輪速センサの検出結果に基づいて取得される複数の駆動輪の各々の回転速度と、第２の車輪速センサの検出結果に基づいて取得される複数の従動輪の回転速度の平均値と、に基づいて、駆動輪ごとにスリップ比を算出する。このような構成によれば、従動輪の回転速度については平均をとることで合わせて考慮し、駆動輪の回転速度については個別に考慮することで、駆動輪ごとにスリップ比を容易に推定することができる。 More specifically, in the embodiment, when a plurality of driving wheels and a plurality of driven wheels are present, the estimation unit 203 increases the rotation speed of each of the plurality of driving wheels acquired based on the detection result of the first wheel speed sensor. And, based on the average value of the rotation speeds of the plurality of driven wheels acquired based on the detection result of the second wheel speed sensor, the slip ratio is calculated for each drive wheel. According to such a configuration, the rotation speed of the driven wheels is taken into consideration by taking an average, and the rotation speed of the driving wheels is taken into consideration individually, so that the slip ratio can be easily estimated for each driving wheel. be able to.

ここで、実施形態において、取得部２０２は、車両Ｖの走行状態に関する情報を検出する車載センサとしての車輪速センサ３１、操舵センサ３２、および勾配センサ３３の検出結果を取得し、制御部２０１は、車載センサの検出結果に応じて、駆動輪として駆動させる車輪１０と、従動輪として駆動させる車輪１０と、を決定する。このような構成によれば、車両Ｖの走行状態を考慮して、駆動輪および従動輪の個数および位置を適切に決定することができる。 Here, in the embodiment, the acquisition unit 202 acquires the detection results of the wheel speed sensor 31, the steering sensor 32, and the gradient sensor 33 as vehicle-mounted sensors that detect information on the driving state of the vehicle V, and the control unit 201 acquires the detection results. The wheel 10 to be driven as a driving wheel and the wheel 10 to be driven as a driven wheel are determined according to the detection result of the vehicle-mounted sensor. According to such a configuration, the number and position of the driving wheels and the driven wheels can be appropriately determined in consideration of the traveling state of the vehicle V.

より具体的に、実施形態において、制御部２０１は、車載センサの検出結果が、車両Ｖが路面としての傾斜面を上る方向に進むことを示す場合、複数の車輪１０のうち車両Ｖの進行方向の前側に設けられた複数の前側車輪が、複数の車輪１０のうち車両Ｖの進行方向の後側に設けられた複数の後側車輪よりも数多く駆動輪として駆動するように、駆動装置２０を制御しうる（図４参照）。また、制御部２０１は、車両Ｖの走行状態が、車両Ｖが傾斜面を下る方向に進むという状態である場合、複数の後側車輪が複数の前側車輪よりも数多く駆動輪として駆動するように、駆動装置２０を制御しうる（図５参照）。このような構成によれば、登坂時には、車両Ｖを前から引っ張る形で駆動力が発生するように前側車輪の方を数多く駆動輪とすることで、車両Ｖの挙動を安定化させながら、摩擦係数を適切に推定することができる。また、降坂時には、たとえば回生ブレーキをかけた際に車両Ｖを後ろから引っ張る形で制動力が発生するように後側車輪の方を数多く駆動輪とすることで、車両Ｖの挙動を安定化させながら、摩擦係数を適切に推定することができる。 More specifically, in the embodiment, when the detection result of the vehicle-mounted sensor indicates that the vehicle V advances in the direction of going up the inclined surface as the road surface, the traveling direction of the vehicle V among the plurality of wheels 10 The drive device 20 is driven so that the plurality of front wheels provided on the front side of the vehicle drive more as drive wheels than the plurality of rear wheels provided on the rear side in the traveling direction of the vehicle V among the plurality of wheels 10. It can be controlled (see FIG. 4). Further, the control unit 201 causes the plurality of rear wheels to be driven as more driving wheels than the plurality of front wheels when the traveling state of the vehicle V is such that the vehicle V advances in the direction of descending the inclined surface. , The drive device 20 can be controlled (see FIG. 5). According to such a configuration, when climbing a slope, a large number of front wheels are used as driving wheels so that a driving force is generated by pulling the vehicle V from the front, so that the behavior of the vehicle V is stabilized and friction is generated. The coefficient can be estimated appropriately. In addition, when descending a slope, the behavior of the vehicle V is stabilized by using a large number of rear wheels as driving wheels so that braking force is generated by pulling the vehicle V from behind, for example, when regenerative braking is applied. The coefficient of friction can be estimated appropriately.

また、実施形態において、制御部２０１は、車載センサの検出結果が、車両Ｖが旋回を行うことを示す場合、複数の車輪１０のうち旋回の外側に設けられた複数の外側車輪が、複数の車輪１０のうち旋回の内側に設けられた複数の内側車輪よりも数多く駆動輪として駆動するように、駆動装置２０を制御しうる（図６および図７参照）。このような構成によれば、外側車輪に内側車輪よりも大きな駆動力を発生させることで、旋回の際の車両Ｖの挙動の安定化を図りながら、摩擦係数を適切に推定することができる。 Further, in the embodiment, when the detection result of the vehicle-mounted sensor indicates that the vehicle V makes a turn, the control unit 201 has a plurality of outer wheels provided outside the turn among the plurality of wheels 10. The drive device 20 can be controlled so that it is driven as more drive wheels than a plurality of inner wheels provided inside the turn among the wheels 10 (see FIGS. 6 and 7). According to such a configuration, by generating a driving force larger than that of the inner wheel on the outer wheel, the friction coefficient can be appropriately estimated while stabilizing the behavior of the vehicle V at the time of turning.

また、実施形態において、制御部２０１は、車載センサの検出結果が、車両Ｖが直進することを示す場合、複数の車輪１０のうち車両Ｖの左右方向の一方側で進行方向に沿って設けられた複数の一方車輪のうち少なくとも２つが駆動輪として駆動するか、または、複数の車輪１０のうち左右方向の他方側で進行方向に沿って設けられた複数の他方車輪のうち少なくとも２つが駆動輪として駆動するように、駆動装置２０を制御しうる（図６および図７参照）。このような構成によれば、複数の一方車輪のうち少なくとも２つ、または、複数の他方車輪のうち少なくとも２つを駆動輪として駆動させることで、同じ位置（領域）の摩擦係数を２回推定し、摩擦係数の推定精度を高めることができる。 Further, in the embodiment, when the detection result of the vehicle-mounted sensor indicates that the vehicle V travels straight, the control unit 201 is provided on one side of the plurality of wheels 10 in the left-right direction of the vehicle V along the traveling direction. At least two of the plurality of one wheels are driven as driving wheels, or at least two of the plurality of wheels 10 are provided along the traveling direction on the other side in the left-right direction. The drive device 20 can be controlled so as to be driven as (see FIGS. 6 and 7). According to such a configuration, the friction coefficient at the same position (region) is estimated twice by driving at least two of the plurality of one wheels or at least two of the plurality of other wheels as driving wheels. However, the estimation accuracy of the friction coefficient can be improved.

この場合において、制御部２０１は、複数の一方車輪のうち少なくとも１つと、複数の他方車輪のうち少なくとも１つと、が駆動輪として駆動するように、駆動装置２０を制御しうる（図６および図７参照）。そして、推定部２０３は、路面上における複数の一方車輪に対応した一方領域の摩擦係数としての第１の摩擦係数と、路面上における他方車輪に対応した他方領域の摩擦係数としての第２の摩擦係数と、を推定しうる。そして、制御部２０１は、第１の摩擦係数と第２の摩擦係数との大小関係に応じて、複数の一方車輪と複数の他方車輪とのうちいずれを数多く駆動輪として駆動させるかを決定しうる。このような構成によれば、たとえば、一方領域および他方領域のうち、駆動輪が一輪あたりに路面に伝達可能な駆動力が相対的に小さい滑りやすい方の領域に、駆動輪が一輪あたりに路面に伝達可能な駆動力が相対的に大きい滑りにくい方の領域よりも数多く駆動輪を配置することで、必要な駆動力を分散して確保しやすくすることができる。したがって、車両Ｖの挙動の安定化を図りながら、摩擦係数を適切に推定することができる。 In this case, the control unit 201 can control the drive device 20 so that at least one of the plurality of one wheels and at least one of the plurality of other wheels are driven as drive wheels (FIGS. 6 and 6). 7). Then, the estimation unit 203 has a first friction coefficient as a friction coefficient of one region corresponding to a plurality of one wheels on the road surface and a second friction as a friction coefficient of the other region corresponding to the other wheel on the road surface. The coefficient and can be estimated. Then, the control unit 201 determines which of the plurality of one wheels and the plurality of other wheels is driven as a large number of driving wheels according to the magnitude relationship between the first friction coefficient and the second friction coefficient. sell. According to such a configuration, for example, in one region and the other region, in the slippery region where the driving force that the driving wheels can transmit to the road surface per wheel is relatively small, the driving wheels are on the road surface per wheel. By arranging more driving wheels than in the non-slip area where the driving force that can be transmitted to the vehicle is relatively large, it is possible to disperse and secure the required driving force. Therefore, the coefficient of friction can be appropriately estimated while stabilizing the behavior of the vehicle V.

なお、実施形態において、路面状態推定装置２００は、推定部２０３により推定された摩擦係数と閾値との比較結果に応じて、車両Ｖに設けられた通知部４０を介して所定の通知を出力する出力部２０４をさらに備えている。このような構成によれば、車両Ｖの乗員に対して摩擦係数と閾値との比較結果に応じた通知を容易に出力することができる。 In the embodiment, the road surface condition estimation device 200 outputs a predetermined notification via the notification unit 40 provided in the vehicle V according to the comparison result between the friction coefficient estimated by the estimation unit 203 and the threshold value. It further includes an output unit 204. According to such a configuration, it is possible to easily output a notification according to the comparison result between the friction coefficient and the threshold value to the occupant of the vehicle V.

また、実施形態において、推定部２０３は、摩擦係数を、路面上における駆動輪に対応した領域の位置に関する位置情報と対応付けて記憶部２０３ａに記憶する。このような構成によれば、路面の摩擦係数を位置ごとに細かく分けて把握することができる。 Further, in the embodiment, the estimation unit 203 stores the friction coefficient in the storage unit 203a in association with the position information regarding the position of the region corresponding to the drive wheel on the road surface. According to such a configuration, the coefficient of friction of the road surface can be grasped by dividing it into small parts for each position.

以上、本開示の実施形態を説明したが、上述した実施形態はあくまで一例であって、発明の範囲を限定することは意図していない。上述した新規な実施形態は、様々な形態で実施されることが可能であり、発明の要旨を逸脱しない範囲で、種々の省略、置き換え、変更を行うことができる。上述した実施形態およびその変形は、発明の範囲や要旨に含まれるとともに、特許請求の範囲に記載された発明とその均等の範囲に含まれる。 Although the embodiments of the present disclosure have been described above, the above-described embodiments are merely examples and are not intended to limit the scope of the invention. The novel embodiment described above can be implemented in various forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The above-described embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

１０ 車輪
１０ＦＬ 前輪（車輪）
１０ＦＲ 前輪（車輪）
１０ＲＬ 後輪（車輪）
１０ＲＲ 後輪（車輪）
２０、２０ＦＬ、２０ＦＲ、２０ＲＬ、２０ＲＲ 駆動装置
３１、３１ＦＬ、３１ＦＲ、３１ＲＬ、３１ＲＲ 車輪速センサ（車載センサ）
３２ 操舵センサ（車載センサ）
３３ 勾配センサ（車載センサ）
２００ 路面状態推定装置
２０１ 制御部
２０２ 取得部
２０３ 推定部
２０３ａ 記憶部
２０４ 出力部
Ｖ 車両 10 wheels 10FL front wheels (wheels)
10FR front wheel (wheel)
10RL rear wheel (wheel)
10RR rear wheel (wheel)
20, 20FL, 20FR, 20RL, 20RR Drive unit 31, 31FL, 31FR, 31RL, 31RR Wheel speed sensor (vehicle-mounted sensor)
32 Steering sensor (vehicle-mounted sensor)
33 Gradient sensor (vehicle-mounted sensor)
200 Road surface condition estimation device 201 Control unit 202 Acquisition unit 203 Estimating unit 203a Storage unit 204 Output unit V Vehicle

Claims (9)

路面を走行する車両に設けられた複数の車輪のうち一部が駆動輪として駆動し、前記複数の車輪のうち残りの一部が従動輪として従動するように、前記複数の車輪をそれぞれ独立に駆動可能な駆動装置を制御する制御部と、
前記複数の車輪の回転速度をそれぞれ検出する複数の車輪速センサの検出結果を取得する取得部と、
前記複数の車輪速センサのうち前記駆動輪の回転速度を検出する第１の車輪速センサの検出結果と、前記複数の車輪速センサのうち前記従動輪の回転速度を検出する第２の車輪速センサの検出結果と、に基づいて、前記駆動輪ごとにスリップ比を算出し、当該スリップ比に基づいて、前記路面上における前記駆動輪に対応した領域ごとに摩擦係数を推定する推定部と、
を備える、路面状態推定装置。 The plurality of wheels are independently driven so that a part of the plurality of wheels provided on the vehicle traveling on the road surface is driven as a driving wheel and the remaining part of the plurality of wheels is driven as a driven wheel. A control unit that controls a driveable drive unit and
An acquisition unit that acquires detection results of a plurality of wheel speed sensors that detect the rotation speeds of the plurality of wheels, respectively.
The detection result of the first wheel speed sensor that detects the rotation speed of the driving wheel among the plurality of wheel speed sensors, and the second wheel speed that detects the rotation speed of the driven wheel among the plurality of wheel speed sensors. An estimation unit that calculates the slip ratio for each drive wheel based on the detection result of the sensor and estimates the friction coefficient for each region corresponding to the drive wheel on the road surface based on the slip ratio.
A road surface condition estimation device. 前記推定部は、前記駆動輪および前記従動輪がそれぞれ複数存在する場合、前記第１の車輪速センサの検出結果に基づいて取得される複数の前記駆動輪の各々の回転速度と、前記第２の車輪速センサの検出結果に基づいて取得される複数の前記従動輪の回転速度の平均値と、に基づいて、前記駆動輪ごとに前記スリップ比を算出する、
請求項１に記載の路面状態推定装置。 When a plurality of the driving wheel and the driven wheel are present, the estimation unit includes the rotation speed of each of the plurality of driving wheels acquired based on the detection result of the first wheel speed sensor, and the second driving wheel. The slip ratio is calculated for each of the driving wheels based on the average value of the rotational speeds of the plurality of driven wheels acquired based on the detection result of the wheel speed sensor.
The road surface condition estimation device according to claim 1. 前記取得部は、前記複数の車輪の回転速度をそれぞれ検出する前記複数の車輪速センサを含む、前記車両の走行状態に関する情報を検出する車載センサの検出結果を取得し、
前記制御部は、前記車載センサの検出結果に応じて、前記駆動輪として駆動させる車輪と、前記従動輪として駆動させる車輪と、を決定する、
請求項１または２に記載の路面状態推定装置。 The acquisition unit acquires the detection result of an in-vehicle sensor that detects information on the running state of the vehicle, including the plurality of wheel speed sensors that detect the rotational speeds of the plurality of wheels.
The control unit determines a wheel to be driven as the driving wheel and a wheel to be driven as the driven wheel according to the detection result of the vehicle-mounted sensor.
The road surface condition estimation device according to claim 1 or 2. 前記制御部は、
前記車載センサの検出結果が、前記車両が前記路面としての傾斜面を上る方向に進むことを示す場合、前記複数の車輪のうち前記車両の進行方向の前側に設けられた複数の前側車輪が、前記複数の車輪のうち前記車両の前記進行方向の後側に設けられた複数の後側車輪よりも数多く前記駆動輪として駆動するように、前記駆動装置を制御し、
前記車両の走行状態が、前記車両が前記傾斜面を下る方向に進むという状態である場合、前記複数の後側車輪が前記複数の前側車輪よりも数多く前記駆動輪として駆動するように、前記駆動装置を制御する、
請求項３に記載の路面状態推定装置。 The control unit
When the detection result of the vehicle-mounted sensor indicates that the vehicle advances in the direction of going up the inclined surface as the road surface, the plurality of front wheels provided on the front side in the traveling direction of the vehicle among the plurality of wheels are used. The driving device is controlled so as to drive as the driving wheels more than the plurality of rear wheels provided on the rear side of the vehicle in the traveling direction among the plurality of wheels.
When the traveling state of the vehicle is a state in which the vehicle advances in the direction of descending the inclined surface, the driving is such that the plurality of rear wheels are driven as the driving wheels more than the plurality of front wheels. Control the device,
The road surface condition estimation device according to claim 3. 前記制御部は、前記車載センサの検出結果が、前記車両が旋回を行うことを示す場合、前記複数の車輪のうち前記旋回の外側に設けられた複数の外側車輪が、前記複数の車輪のうち前記旋回の内側に設けられた複数の内側車輪よりも数多く前記駆動輪として駆動するように、前記駆動装置を制御する、
請求項３または４に記載の路面状態推定装置。 When the detection result of the vehicle-mounted sensor indicates that the vehicle makes a turn, the control unit means that the plurality of outer wheels provided outside the turn are among the plurality of wheels. The drive device is controlled so that it is driven as the drive wheels more than the plurality of inner wheels provided inside the turn.
The road surface condition estimation device according to claim 3 or 4. 前記制御部は、前記車載センサの検出結果が、前記車両が直進することを示す場合、前記複数の車輪のうち前記車両の左右方向の一方側で進行方向に沿って設けられた複数の一方車輪のうち少なくとも２つが前記駆動輪として駆動するか、または、前記複数の車輪のうち前記左右方向の他方側で前記進行方向に沿って設けられた複数の他方車輪のうち少なくとも２つが前記駆動輪として駆動するように、前記駆動装置を制御する、
請求項３〜５のうちいずれか１項に記載の路面状態推定装置。 When the detection result of the vehicle-mounted sensor indicates that the vehicle is going straight, the control unit has a plurality of one wheels provided along the traveling direction on one side of the plurality of wheels in the left-right direction of the vehicle. At least two of them are driven as the driving wheels, or at least two of the other wheels provided along the traveling direction on the other side of the left and right directions are the driving wheels. Control the driving device to drive,
The road surface condition estimation device according to any one of claims 3 to 5. 前記制御部は、前記複数の一方車輪のうち少なくとも１つと、前記複数の他方車輪のうち少なくとも１つと、が前記駆動輪として駆動するように、前記駆動装置を制御し、
前記推定部は、前記路面上における前記複数の一方車輪に対応した一方領域の前記摩擦係数としての第１の摩擦係数と、前記路面上における前記他方車輪に対応した他方領域の前記摩擦係数としての第２の摩擦係数と、を推定し、
前記制御部は、前記第１の摩擦係数と前記第２の摩擦係数との大小関係に応じて、前記複数の一方車輪と前記複数の他方車輪とのうちいずれを数多く前記駆動輪として駆動させるかを決定する、
請求項６に記載の路面状態推定装置。 The control unit controls the drive device so that at least one of the plurality of one wheels and at least one of the plurality of other wheels are driven as the drive wheels.
The estimation unit serves as a first friction coefficient as the friction coefficient of one region corresponding to the plurality of one wheels on the road surface and as the friction coefficient of the other region corresponding to the other wheel on the road surface. Estimate the second coefficient of friction,
Which of the plurality of one wheels and the plurality of other wheels is driven as the driving wheels by the control unit according to the magnitude relationship between the first friction coefficient and the second friction coefficient. To decide,
The road surface condition estimation device according to claim 6. 前記推定部により推定された前記摩擦係数と閾値との比較結果に応じて、前記車両に設けられた通知部を介して所定の通知を出力する出力部をさらに備える、
請求項１〜７のうちいずれか１項に記載の路面状態推定装置。 An output unit that outputs a predetermined notification via a notification unit provided in the vehicle is further provided according to the comparison result between the friction coefficient and the threshold value estimated by the estimation unit.
The road surface condition estimation device according to any one of claims 1 to 7. 前記推定部は、前記摩擦係数を、前記路面上における前記駆動輪に対応した前記領域の位置に関する位置情報と対応付けて記憶部に記憶する、
請求項１〜８のうちいずれか１項に記載の路面状態推定装置。 The estimation unit stores the friction coefficient in the storage unit in association with position information regarding the position of the region corresponding to the drive wheel on the road surface.
The road surface condition estimation device according to any one of claims 1 to 8.
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